thank you very much! I read through the documentation and have prepared more questions!
I also found this which was helpful:
http://2zzge.com/library/1ZZFE/1zzfe.pdf
Notes:
1.
intake camshaft timing
The intake cam advance is under control of the ECU, for ALL engine speeds!
"The system changes valve timing over the entire speed range in accordance to engine speed and load."
2.
valve LIFT
It seems as though this feature is intended to be "locked"- we cannot adjust the moment of the valve lift increase (via ECU).
"...also changes valve lift and event angles at 6000rpm from low to high"
3.
valve springs
A typical problem with any combustion engine relying on valvesprings is that a valvetrain instability may occur at specific frequencies which affects the valve closing event, it has been given names such as "valve float".
I have noted that this documentation includes research directed towards the "stability" of the valvetrain, specifically with regards to the valve springs and the closing events.
"Valve lift acceleration was changed to improve
resonance, and rocker arm rigidity was increased to
improve deflection."
Many aftermarket camshafts alter the lift characteristics, which would affect the resonant frequencies, since the fix was applied to the camshaft instead of the springs themselves. Changing valvesprings would seem to be a fix, except that this typically means a stronger spring, which may not be a reliable change, since rocker arm durability/deflection was tested and confirmed for OEM camshafts ONLY.... there is no way to guarantee abnormal wear and tear associated with aftermarket valve springs will not occur.
My question here is
(#3)... How is the community, over the past years, handling and testing the aftermarket valve springs? Have there been component failures due to the aftermarket springs? Have there been issues with breaking components or unreliable valve seals? has anybody driven one of these engines for 150,000 miles with aftermarket camshafts/springs?
Does anybody have OEM flow numbers for the head at variable lifts?
4.
Compression, turbochargers, cast components.
I see the engine is designed around the idea of lightweight naturally aspirated fuel economy fun.
As for turbocharging, the compression seems a bit high to maximize the potential of pump gas. I feel that with
9:1 compression the engine should be able to produce about 400 horsepower by 7,000rpm with 93 octane, if it is anything like a typical 4-cylinder engine.
But because the compression is higher than 9:1, I would expect a limitation to be imposed by the octane being used. For 93 octane,
without an intercooler, 10:1 compression would be safe up to about 7psi of efficient pressure above atmospheric, depending of course upon the design and shape of the combustion chambers, as well as any helmholtz acoustic tuning that was done which might improve VE at specific points, giving an abnormally high peak torque number which may instigate pre-ignition... That is why #4 is here... I must ask:
A. What are the typical power and boost numbers acheived while using the 1zz AND 2zz engines with OEM components/compression and a turbocharger?
B. What is the capability of the water/air intercooler I see being used? Can it support 30lb/min? 40lb/min?
C. Durability... are there MANY cast piston failures when turbocharging the OEM bottom end? If so, where associated, the piston ring likely?
Guesses, just for fun:
I would
guess, that maximum safe boost is about 10psi on the 1zz while using an air/water intercooler. And 7psi for the 2zz with the same intercooler.
While using the OEM bottom end. Assumed compressor flow of 32-35 lb/min maximum for best efficiency island characteristics.
